1. Field of the Invention
The present invention generally relates to cooling systems for electronic devices used in, for example, a computer using a large number of LSI devices having a high heat density, and more particularly to a cooling system in which a coolant is circulated.
2. Description of the Prior Art
Conventionally, a cooling system is used to cool electronic devices. For example, Japanese Laid-Open Patent Application No. 55-26605 discloses a cooling system for electronic devices in which a coolant is made to circulate. Particularly, the cooling system disclosed in the above application is intended to keep the pressure in a primary coolant circulatory system constant by means of a bypass connecting input and output gates of a pump. The feature of the cooling system disclosed in the above application is that it does not have a tank for reserving a coolant and the operation of pressure is based on a characteristic of variation in the delivery pressure of the pump with respect to the flow rate of the circulating coolant. However, in such a cooling system, a higher flow rate of the coolant, than that of the coolant flowing in a coolant path for cooling the electronic parts, flows in the bypass with respect to a variation in the pressure of the overall circulatory system caused by a temperature variation in the closed system. Hence, it is difficult to realize stable cooling.